Differential pressure fluid flow regulating device

Abstract

A fluid flow regulating device comprising a housing defining an inlet, an outlet orifice, and a fluid flow passage therein between the inlet and the outlet orifice, a movable piston in the housing having an upstream surface and a downstream surface exposed to fluid flowing through the passage, means for providing a drop in pressure between the upstream surface and the downstream surface as a function of fluid flow rate through the device, and a closure member that is connected to the movable piston and has an externally curved surface that is movable between positions adjacent to and in front of the outlet orifice as the piston moves in response to changes in the magnitude of the drop in pressure.

What is claimed is: 
     
       1. A fluid flow regulating device comprising a housing defining an inlet, an outlet orifice having an outlet axis along the direction of flow through it, and a fluid flow passage therein between said inlet and said outlet orifice,   a movable piston in said housing having an upstream surface and a downstream surface exposed to fluid flowing through said passage,   a spring biasing said piston in the upstream direction,   means for providing a drop in pressure between said upstream surface and said downstream surface as a function of fluid flow rate through said device, and   a closure member that is connected to said movable piston and has an externally curved surface that is movable along a closure member path perpendicular to said outlet axis between positions adjacent to and in front of said outlet orifice as said piston moves in response to changes in the magnitude of said drop in pressure, said surface being curved about an axis that is perpendicular to both said outlet axis and said closure member path,   said closure member being movable so as to permit pivoting of said closure member about an edge of said housing defining said outlet orifice at a point of contact of said closure member with said edge.     
     
     
       2. The fluid flow regulating device of claim 1 wherein said externally curved surface is a portion of a sphere, and wherein said outlet orifice is circular in shape, having a smaller diameter than the diameter of said portion of a sphere. 
     
     
       3. The fluid flow regulating device of claim 2 wherein said closure member is a spherical ball mounted for rotation on a first dowel passing through its center, the longitudinal axis of said first dowel being transverse to the direction of movement of said piston and said curved surface. 
     
     
       4. The fluid flow regulating device of claim 3 wherein said housing includes a pair of guide ribs extending into said fluid flow passage opposite said outlet orifice, said guide ribs being spaced and positioned to restrict movement of said ball along said first dowel, to maintain said spherical ball in the vicinity of said outlet orifice. 
     
     
       5. The fluid flow regulating device of claim 3 wherein said dowel is mounted between the ends of two transverse supports that are pivotally connected to said movable piston. 
     
     
       6. The fluid flow regulating device of claim 5 wherein said pair of supports are connected to said piston via a second dowel extending between the other ends of them, said second dowel passing through slots on said piston extending in the direction of movement of said piston. 
     
     
       7. The fluid flow regulating device of claim 1 wherein said piston has a restricted flow passage through it to provide said drop in pressure. 
     
     
       8. The fluid flow regulating device of claim 1 wherein said piston is in the shape of a flat plate positioned transverse to the direction of flow, and further comprising a diaphragm supported on the upstream side of said plate and sealed at its periphery to said housing. 
     
     
       9. The fluid flow regulating device of claim 8 wherein said housing comprises two pieces sealing between them the periphery of said diaphragm. 
     
     
       10. The fluid flow regulating device of claim 1 wherein said movable piston is biased in the upstream direction via an extension spring. 
     
     
       11. The fluid flow regulating device of claim 10 wherein said extension spring is connected to an adjustable support that is adjustably positioned within said housing. 
     
     
       12. The fluid flow regulating device of claim 11 wherein said adjustable support is mounted on a threaded shaft within said housing, further comprising means to rotate said threaded shaft to thereby extend or contract said spring. 
     
     
       13. The fluid flow regulating device of claim 12 wherein the end of said threaded shaft passes through the center of said extension spring. 
     
     
       14. The fluid flow regulating device of claim 1 wherein said closure member is rotatably mounted about an axis of rotation, said axis of rottion being movable along said closure member path.